Friday, April 10, 2009

Finally Some Movement in the Upper Midwest

The image above shows some pretty good movement in the far western Great Lakes region and the eastern Great Plains. This is the best movement I've seen this spring so I'm expecting some species to be gone or in much reduced numbers tomorrow, for example Redpolls and Juncos. In their place I would expect (and hope) to see new spring migrants like Hermit Thrushes, Eastern Phoebes and waterfowl who will be finding many of the lakes open now.

Images from individual nexrad stations like Minneapolis show the classic "green donut" which is the shape produced as migrants pass over an area. However, there are conditions that will cause the images to vary.

This image from Brownsville, Texas shows migrants passing over the area but because the city is on the coast and birds don't fly over water unless they have to, the image is "half a donut". The migrating flocks follow the shoreline but don't venture out over the gulf. It also appeared like there might be some movement along the gulf coast to the east behind the strong storm front that produced the strong storms in Alabama and Georgia tonight.

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